1. Field of the Invention
The present invention relates to a buckle including a socket and a plug that can be manually attached to and detached from each other and more particularly to a buckle for coupling each end of a tape-shaped member such as a belt together and separating the ends from each other.
2. Description of Related Art
Conventionally, a buckle has been used for coupling each end of a tape-shaped member such as a belt together and separating the ends from each other (document 1: Japanese Patent Laid-Open publication No. 2003-284606; document 2: U.S. Pat. No. 5,926,928).
The buckle includes a socket having an opening in a front end side and a plug that can be detachably engaged with the socket when being inserted in the socket.
When inserting the plug into the socket, a longitudinal axis of the socket and a longitudinal axis of the plug are aligned in parallel and then the plug is inserted straight into the socket in the state. Thus, the plug is inserted in and engaged with the socket.
Note that, when an insertion slot is defined in a front end of a socket and a plug is inserted with a front end thereof first into the insertion slot of the socket, the longitudinal axis of the socket is an axis that passes the gravity center of the socket and extends from the insertion slot toward the inside of the socket, while the longitudinal axis of the plug is an axis that passes the gravity center of the plug and extends from a front end toward a back end of the plug.
In the conventional buckle, the longitudinal axes of the socket and the plug need to be aligned before the socket is inserted into the plug, requiring effort in adjusting relative postures of the socket and the plug.
In addition, if a user attempts to insert the plug into the socket without aligning the longitudinal axes of the socket and the plug beforehand, the plug may not be inserted into the socket or may be stuck halfway, causing a problem that the plug needs to be separated from the socket and reinserted to the plug after aligning the longitudinal axes of the socket and the plug.
When considering actual situations where the buckle is used, for instance, in a situation where the buckle is used for securely tightening a belt of a bag, a user tends to insert the plug into the socket fixed on the bag only with the plug in a hand (not both of the socket and plug). In this case, since the longitudinal axes of the socket and the plug cannot be easily aligned, the user may be imposed to try to reinsert the plug many times, deteriorating the usability.